1. Field of the Invention
The present invention relates to skylight systems for standing seam roofs, shingle roofs and sunrooms, and more particularly to standing seam skylight systems providing simple and leakproof installations thereof.
2. Description of the Prior Art
The use of skylights in residences as well as commercial buildings has become widespread in recent years with the advent of low cost and rugged plastic dome skylights. Self flashing plastic skylights are popular, partly due to economies in eliminating extensive curb construction. However, some skill is required if a leakproof installation is to be achieved and some customer dissatisfaction has occurred from poor installation practices.
Certain types of roofs have not been suitable for skylight installation. For example, it is common in the southern parts of the United States to construct patios, porches and the like using sheet metal standing seam roofing. A typical roof of this type utilizes long panels having upturned edges. The panels are laid side by side with the upstanding edge of one panel contiguous with the upstanding edge of adjacent panels. The upper edges of the upstanding portions may be bent at right angles or rolled. In either style, an interlocking bead is provided which snaps over the contiguous upstanding portions of the panels. This type of roof also is widely used for industrial buildings.
Although it is desirable in many installations to install skylights in a standing seam roof, difficulty has been experienced in adapting standard plastic dome type skylights to the standing seam metal roofs. Self flashing skylights have been used which must be screwed to the metal and require caulking compound to prevent leaking. However, due to the differing expansion coefficients of the plastic and sheet metal, it has been found very difficult to prevent leaks. Furthermore, openings must be cut into the metal which reduce the strength of the roof and add to the labor cost.
There have been attempts to overcome these problems. For example, it is known to form a narrow continuous panel of acrylic plastic or the like which will simply replace a standard metal roof panel and which runs the entire length of the roof. It is apparent that this type of unit must be narrower than a standard roof panel since the plastic lacks the required strength for a full width panel.
Problems have also arisen in installing self flashing plastic skylights in shingled roofs and care must be taken to ensure freedom from leaks. This problem is compounded when a so-called sunroof, formed by joining a plurality of plastic skylights together, is desired. A common approach to this problem is to build a "curb" which extends above the plane of the roof. The curb is a box-like structure made of wood, aluminum, fiberglass or similar material. A competent roofer can then install flashing, such as step flashings, around the curb and produce an essentially leakfree structure. The skylight is then installed on top of the curb and includes a drip mold projecting down and over the curb edge.
The disadvantage to this solution is that the curb is expensive to construct and install, requiring relatively skilled labor. It is also unsightly, since it produces the appearance of a hatch projecting from the roof plane. The curb also has the disadvantage of acting as a dam to trap water, snow, ice, leaves and other debris on the roof. On roofs with a low pitch, it is common to construct a sloping curb to increase the pitch of the skylight.
There is a need for a plastic dome type skylight which can be installed at any point along a metal roof panel without cutting an opening in the metal panel, which will not experience difficulties with leakage and which can be installed in a shingled roof with the same watertight integrity that is obtainable with curb type installations. Additionally, there is a need for a self flashed skylight which can be overlapped with others to form a leakproof sunroof.